Forced-draft hollow grate-bar.



J. H. DIETZ.

FORGED DRAFT HOLLOW GRATE BAR.

APPLICATION FILED MAY 8, 1913.

i l a I Patented June 16, 1914.

sses Inventor JOHN H. DIETZ, OF KANSAS CITY, M IISSOUBI.

FORCED-DRAFT HOLLOW GRATE-BAR.

Specification of Letters Patent.

Patented J line 16, 1914.

Application filed May 3, 1913. Serial no. 765,251.

To all whom it may concern Be it known that I, J OHN HALIFAX Dinrz,

- a citizen of the United States, residing at stalled and cheaply maintained grate baris produced.

Another object is to provide a'grate bar with a device for easily and completely cleaning the interior of the bar of ashes or clinkers, at the same time keeping it air tight when used with forced draft and providing large openings or air ways for operating the grate under natural draft.

A third object is to provide an improved means of controlling and regulating the quantity of air delivered through the grate bar tothe combustible.

I attain these objects by means of the mechanism illustrated in the accompanying drawing, in which:

Figure 1, is a top view of one grate bar; Fig. 2, a side view of the same bar; Fig. 3, a longitudinal section of the bar with one side removed showing a side view not sectioned, of the interior parts; Fig. 4, a view of the front end of two bars showing relative position of barswhen assembled to form a furnace floor; F ig; 5, a vertical cross section of the bar on the line as y; and Fig. 6, a bottom view of one of the adjustable twyer blocks.

Similar letters refer to similar parts throughout the several views.

The shell of the forced draft grate bar of my invention is formed of two parts, the lower part, lettered j being triangular in section and of any length required. The ends of this lower part have extending lugs for supporting the bar on the coking plate or standard grate rests such as are used'in boiler furnaces, and at the rear end it is provided with an air duct connection h arranged for connection of each grate to the air duct, under the furnace floor, which extends to a fan or blower. The bottom of this lower part of the bar is circular in cross section and provided with clean cut openings 7", which are also used for the admission of air when the grate is operated on natural or induced draft. These openings are closed by a rotating bar cl which has two or more wings or vanes so that in one position two of the wings cover the clean out openings and byrotating the bar d slightly the openings are uncovered and the wings scrape any ashes or clinkers from the inside of the bar and discharge them through the openings into the ash pit. This bar d is provided with adjustable trunnions and bearings 0 to hold it in contact with the bottomof the grate bar and one end it is squared and provided with a bell crank g. The bell cranks of a set of grates may be connected by a bar or arm p which is operated by a shaking lever on the outside of the furnace or boiler setting.

The upper part of the grate bar, lettered a, is formed of a flat top or plate resting on the lower part by a beveled surface so designed that the unequal expansion does not produce a strain between the parts. The upper part having the higher temperature and the greater expansion simply settles lower and retains the tight joint between the two. The top plate a has a longitudinal rib is on the under side which prevents warping and acts as a support for the inclined lugs n on-the under side of the twyer blocks 6. The twyer blocks 6 are spaced at intervals along the top plate a and are set in same with beveled edges at a slight distance from the beveled openings in the plate a so that they form air vents narrow at the top edge and wider at the bottom to give clearance and prevent clogging. The openings in the plate a are provided with extending lugs s which engage the inclined slots m in the twyer blocks b The twyer blocks are each provided with a depending lug or pin Z which drops into a hole in the angle or bar 2'. This bar is supported at each end or at intervals in its length in such a way as to allow it to slide freely. A rod or arm (2 attached to the angle or bar extends through the end of the grate bar and is provided with a handle or hell crank so that the respective angles in a complete grate may be slid back and forth singly or operated together.

By moving the angle or bar 11 forward each twyer block is rotated through the are of a circle and being supported by the inclined lugs 'n and the inclined slots m it is raised or lowered, depending on the direction of rotation, and proportionate to the length of the arc of movement, thus increasing or decreasing the width of the air vents through the top and consequently regulating the amount of air furnished the combustible through the grate. The slots m in the twyer block also serve to lock the block in place so that it can not be dis turbed by firing tools and at the same time it is readily removable for repairs. By pushing the angle or bar 11 forward until the slots m rotate beyond the lugs s the twyer block may be lifted out and another dropped in place without otherwise disturbing the grate bar. 'The complete top a may also be removed-without disturbing the grate setting and a new one inserted. The twyer block b has an auxiliary twyer block 0 inserted in its center and held in place by lugs. This may be removed also by rotating until the lugs come opposite slots in the outer block b whenit may be lifted out and a new one inserted.

The width of the bar is designed as a comvmon divisor of standard furnace widths and the bars are set close together giving the maximum number of openings per unit of grate surface; a small recess is left between adjoining bars which may be filled with asbestos cement, sealing the joint between the top plate and grate body and pre-' venting the leakage of air into the ash pit.

By providing large air ways-from a fan and means of adjustment of the twyer block openings in the top plate I make the air restriction and pressure regulation at the surface of the grate in these openings, so that the pressure and volume remain constant at all points ofthe grate surface without regard to the thickness of the fuel bed, and a thin bed or no fuel on one part of the grate does not operate to release the air at this point and reduce the pressure at a point where the bed is thick and air is most needed thus deadening the fire and cooling the combustion chamber with excess air as in other forms of forced draft apparatus.

This grate bar may also be made of one piece, a. c. the top and bottom cast together but using the special devices described above for closin the openings in the bottom and cleaning tie bar of ashes and clinkers, and the adjustable twyer openings in the top substantially as described.

I am aware that, prior to my invention, forced draft hollow grate bars were made with bottom openings and one with adjustable twyer openings. I, therefore, do not claim either broadly, but

I claim:

' 1. The combination of a hollow grate bar provided in its top with a plurality of openings; a plurality of blocks adapted, by vertical movement, to control the respective openings; means for moving the respective blocks vertically on rotation of the blocks; and means for simultaneously rotating the several blocks.

2. The combination of a hollow grate bar provided in its top with a circular opening and with projections at the edge of the opening; a support secured to the bar; a circular block adapted, by vertical movement, to control the opening, the block being provided with depending lugs having inclined faces resting on the support and with inclined slots in its periphery engaging the projections; and means for rotating the block. 1

, 3. The combination of a hollow grate bar provided in'its top with a plurality of circular openings and with projections at the edges of the respective openings; a support secured to the bar; a plurality of blocks adapted, by vertical movement, to control the respective openings, each block being provided with depending arc-shaped lugs having inclined faces resting on the support and with arc-shaped inclined slots in its periphery engaging the respective projections; and means for simultaneously rotating the several blocks.

JOHN H. DIETZ.

lVitnesses:

J. H. EICHMAN, FRANK UHRICH. 

